ben-blinkenlights/ubb-vga/tstimg.c

/*
 * tstimg.c - Generate a test image
 *
 * Written 2011 by Werner Almesberger
 * Copyright 2011 Werner Almesberger
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

/*
 * WARNING: this program does very nasty things to the Ben and it doesn't
 * like company. In particular, it resents:
 *
 * - the MMC driver - disable it with
 *   echo jz4740-mmc.0 >/sys/bus/platform/drivers/jz4740-mmc/unbind
 * - the AT86RF230/1 kernel driver - use a kernel that doesn't have it
 * - anything that accesses the screen - kill GUI, X server, etc.
 * - the screen blanker - either disable it or make sure the screen stays
 *   dark, e.g., with
 *   echo 1 >/sys/devices/platform/jz4740-fb/graphics/fb0/blank
 * - probably a fair number of other daemons and things as well - best to
 *   kill them all.
 */


#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <math.h>

#include "ubb-vga.h"


/* ----- Pixel operations -------------------------------------------------- */


#define	WHITE	0xf


static void pixel(void *f, int xres, int x, int y, uint8_t c)
{
	uint8_t *p;

	p = f+((y*xres+x) >> 1);
	if (x & 1)
		*p = (*p & 0xf0) | c;
	else
		*p = (*p & 0x0f) | (c << 4);
}


/* ----- Color bars -------------------------------------------------------- */


#define	CBAR_X0	0.1
#define CBAR_X1	0.9
#define	CBAR_Y0	0.55
#define	CBAR_Y1	0.75


static void color_bars(void *f, int xres, int yres, ...)
{
	int i, x, y;
	uint8_t c;

	for (i = 0; i < xres*(CBAR_X1-CBAR_X0); i++) {
		x = i+xres*CBAR_X0;
		c = 1+15*i/(xres*(CBAR_X1-CBAR_X0));
		for (y = yres*CBAR_Y0; y < yres*CBAR_Y1; y++)
			pixel(f, xres, x, y, c);
	}
}


/* ----- Grid -------------------------------------------------------------- */


#define	GRID	50


static void grill(void *f, int ares, int bres, int swap)
{
	int n, o;
	int i, a, b;

	n = ares/GRID+1;
	o = (ares % GRID)/2;
	if (!(n & 1)) {
		n--;
		o += GRID/2;
	}
	for (i = 0; i != n; i++) {
		a = o+i*GRID;
		for (b = 0; b != bres; b++)
			if (swap)
				pixel(f, bres, b, a, WHITE);
			else
				pixel(f, ares, a, b, WHITE);
	}

	if (o <= GRID/2) {
		o += GRID/2;
		n--;
	} else {
		o -= GRID/2;
		n++;
	}
	for (i = 0; i != n; i++) {
		a = o+i*GRID;
		for (b = -GRID/4; b != GRID/4; b++)
			if (swap)
				pixel(f, bres, bres/2+b, a, WHITE);
			else
				pixel(f, ares, a, bres/2+b, WHITE);
	}
}


static void grid(void *f, int xres, int yres)
{
	grill(f, xres, yres, 0);
	grill(f, yres, xres, 1);
}


/* ----- Diagonal lines meeting at the sides ------------------------------- */


static void sides(void *f, int xres, int yres)
{
	int i;

	for (i = 0; i != yres/2; i++) {
		pixel(f, xres, i, yres/2-i, WHITE);
		pixel(f, xres, i, yres/2+i, WHITE);
		pixel(f, xres, xres-i-1, yres/2-i, WHITE);
		pixel(f, xres, xres-i-1, yres/2+i, WHITE);
	}
	for (i = 0; i != xres/2; i++) {
		pixel(f, xres, xres/2-i, i, WHITE);
		pixel(f, xres, xres/2+i, i, WHITE);
		pixel(f, xres, xres/2-i, yres-i-1, WHITE);
		pixel(f, xres, xres/2+i, yres-i-1, WHITE);
	}
}


/* ----- Text -------------------------------------------------------------- */


static void dot(void *f, int xres, int x, int y, int color, int side)
{
	int xi, yi;

	for (xi = -side; xi != side+1; xi++)
		for (yi = -side; yi != side+1; yi++)
			pixel(f, xres, x+xi, y+yi, color);
}


static void line45(void *f, int xres, int x, int y, int dx, int dy, int n,
     uint8_t color, int side)
{
	while (n--) {
		dot(f, xres, x, y, color, side);
		x += dx;
		y += dy;
	}
	dot(f, xres, x, y, color, side);
}


static void arc(void *f, int xres, int x, int y, int n, int q,
    uint8_t color, int side)
{
	int dx, dy;

	for (dx = 0; dx != n+1; dx++) {
		dy = sqrt(n*n-dx*dx);
		if (q & 1)
			dot(f, xres, x+dx, y-dy, color, side);
		if (q & 2)
			dot(f, xres, x+dx, y+dy, color, side);
		if (q & 4)
			dot(f, xres, x-dx, y+dy, color, side);
		if (q & 8)
			dot(f, xres, x-dx, y-dy, color, side);
	}
}


static void printc(void *f, int xres, int x, int y, char c, int n,
    uint8_t color, int side)
{
	switch (c) {
	case '0':
		arc(f, xres, x+n, y+n, n, 9, color, side);
		line45(f, xres, x, y+n, 0, 1, 2*n, color, side);
		line45(f, xres, x+2*n, y+n, 0, 1, 2*n, color, side);
		arc(f, xres, x+n, y+3*n, n, 6, color, side);
		break;
	case '1':
		line45(f, xres, x+n, y, 0, 1, 4*n, color, side);
		break;
	case '2':
		arc(f, xres, x+n, y+n, n, 9, color, side);
		line45(f, xres, x+2*n, y+n, 0, 1, n, color, side);
		line45(f, xres, x, y+4*n, 1, -1, 2*n, color, side);
		line45(f, xres, x, y+4*n, 1, 0, 2*n, color, side);
		break;
	case '3':
		arc(f, xres, x+n, y+n, n, 3, color, side);
		arc(f, xres, x+n, y+3*n, n, 3, color, side);
		line45(f, xres, x, y, 1, 0, n, color, side);
		line45(f, xres, x, y+2*n, 1, 0, n, color, side);
		line45(f, xres, x, y+4*n, 1, 0, n, color, side);
		break;
	case '4':
		line45(f, xres, x, y, 0, 1, 2*n, color, side);
		line45(f, xres, x, y+2*n, 1, 0, 2*n, color, side);
		line45(f, xres, x+2*n, y, 0, 1, 4*n, color, side);
		break;
	case '5':
		line45(f, xres, x, y, 1, 0, 2*n, color, side);
		line45(f, xres, x, y, 0, 1, 2*n, color, side);
		line45(f, xres, x, y+2*n, 1, 0, n, color, side);
		arc(f, xres, x+n, y+3*n, n, 7, color, side);
		break;
	case '6':
		arc(f, xres, x+n, y+n, n, 9, color, side);
		line45(f, xres, x, y+n, 0, 1, 2*n, color, side);
		arc(f, xres, x+n, y+3*n, n, 15, color, side);
		break;
	case '7':
		line45(f, xres, x, y, 1, 0, 2*n, color, side);
		line45(f, xres, x+2*n, y, 0, 1, 2*n, color, side);
		line45(f, xres, x, y+4*n, 1, -1, 2*n, color, side);
		break;
	case '8':
		arc(f, xres, x+n, y+n, n, 15, color, side);
		arc(f, xres, x+n, y+3*n, n, 15, color, side);
		break;
	case '9':
		arc(f, xres, x+n, y+n, n, 15, color, side);
		line45(f, xres, x+2*n, y+n, 0, 1, 2*n, color, side);
		arc(f, xres, x+n, y+3*n, n, 6, color, side);
		break;
	case 'x':
		line45(f, xres, x, y+n, 1, 1, 2*n, color, side);
		line45(f, xres, x, y+3*n, 1, -1, 2*n, color, side);
		break;
	case 'A':
		line45(f, xres, x, y+n, 1, -1, n, color, side);
		line45(f, xres, x, y+n, 0, 1, 3*n, color, side);
		line45(f, xres, x+n, y, 1, 1, n, color, side);
		line45(f, xres, x+2*n, y+n, 0, 1, 3*n, color, side);
		line45(f, xres, x, y+2*n, 1, 0, 2*n, color, side);
		break;
	case 'B':
		arc(f, xres, x+n, y+n, n, 3, color, side);
		arc(f, xres, x+n, y+3*n, n, 3, color, side);
		line45(f, xres, x, y, 1, 0, n, color, side);
		line45(f, xres, x, y+2*n, 1, 0, n, color, side);
		line45(f, xres, x, y+4*n, 1, 0, n, color, side);
		line45(f, xres, x, y, 0, 1, 4*n, color, side);
		break;
	case 'G':
		arc(f, xres, x+n, y+n, n, 9, color, side);
		line45(f, xres, x, y+n, 0, 1, 2*n, color, side);
		arc(f, xres, x+n, y+3*n, n, 6, color, side);
		line45(f, xres, x+n, y+2*n, 1, 0, n, color, side);
		line45(f, xres, x+2*n, y+2*n, 0, 1, n, color, side);
		break;
	case 'U':
		line45(f, xres, x, y, 0, 1, 3*n, color, side);
		line45(f, xres, x+2*n, y, 0, 1, 3*n, color, side);
		arc(f, xres, x+n, y+3*n, n, 6, color, side);
		break;
	case 'V':
		line45(f, xres, x, y, 0, 1, 3*n, color, side);
		line45(f, xres, x+2*n, y, 0, 1, 3*n, color, side);
		line45(f, xres, x+n, y+4*n, 1, -1, n, color, side);
		line45(f, xres, x+n, y+4*n, -1, -1, n, color, side);
		break;
	case '-':
		line45(f, xres, x, y+2*n, 1, 0, 2*n, color, side);
		break;
	case ' ':
		break;
	default:
		arc(f, xres, x+n, y+n, n, 9, color, side);
		line45(f, xres, x+n, y+2*n, 1, -1, n, color, side);
		line45(f, xres, x+n, y+3*n, 0, 1, n, color, side);
		break;
	}
}


static void text(void *f, int xres, int x, int y, const char *s, int n,
    uint8_t color, int side)
{
	while (*s) {
		printc(f, xres, x, y, *s, n, color, side);
		x += 3*n;
		s++;
	}
}



static void ctext(void *f, int xres, int x, int y, const char *s, int n,
    uint8_t color, int side)
{
	text(f, xres, x+n*(1-3*(int) strlen(s))/2, y-2*n, s, n, color, side);
}


/* ----- Generate the test image ------------------------------------------- */


void tstimg(void *f, int xres, int yres)
{
	char buf[20];

	memset(f, 0, xres*yres/2);
	grid(f, xres, yres);
	sides(f, xres, yres);
	color_bars(f, xres, yres);
	sprintf(buf, "UBB-VGA %dx%d", xres, yres);
	ctext(f, xres, xres/2, yres/2-GRID*0.75, buf, 10, WHITE, 3);
	ctext(f, xres, xres/2, yres*(CBAR_Y0+CBAR_Y1)/2, buf, 2, 0, 0);
}